Descriptive Psychopathology: The Signs and Symptoms of ...

63 Chapter 3: The brain and psychopathologyassociated with marked apathy and stupor, akinetic mutism and other catatonicfeatures, transcortical motor aphasia, and an inability to start and once startedto stop actions (pathological inertia). Indifference to pain is also reported andis characteristic of catatonia. Diseases affecting this circuit include Parkinson’sand Huntington’s disease, progressive supranuclear palsy, and thalamic lesions.Increased metabolic activity in the region is associated with experiencing moodstates. 49 Seizure foci in this area have been associated with childhood-onset OCD. 50Cerebral hemispheres 51Cortical organizationMultiple cortical areas are involved in the processing of the different aspects ofsensory experience and the organization of the multimodal experience into thefull perception of the immediate external environment. A functional hierarchymoves from primary cortex (receiving the various aspects of modality-specificstimuli), to secondary or unimodal association cortex (organizing the variousaspects of the modality-specific stimuli into a more complex, fuller pattern), andtertiary or heteromodal association cortex (involved in multimodal sensory processing,linking modalities so that they “make sense”). A supramodal associationarea in the frontal lobe connects with subcortical networks and monitors,inhibits, facilitates and manages the heteromodal percepts that are being formed.This area also influences the executive control systems. 52Primary, secondary, and tertiary cerebral cortices configure the temporal,parietal, and occipital lobes of the cerebral hemispheres. 53 With their relatedsubcortical structures they organize and make sense of the external immediateenvironment. This perceptual integration permits recognition of the distinctionbetween self and the external world and an individual’s location in threedimensionalspace. The integrated perceptions and associated information arestored as memory.Frontal circuits and the cerebellum utilize the information in memory torespond to external environmental needs. The hedonistic reward system helpsmaintain responses that were rewarding. The limbic system gives emotionalsalience (meaning) to perceptions and subserves flight/fight mechanisms. Thearousal system provides the tone for these processes to occur, and throughultradian rhythms establishes wakefulness and restorative sleep.Hemisphere functional asymmetryThe two cerebral hemispheres in humans are understood to process informationdifferently.